1. Field of the Invention
The present invention relates to a method for production of a plate denture.
It is important that the surface area of a plate denture to be contacted with an oral mucosa (mucosal surface) have a dimensionally precise configuration. A dough-like resin undergoes shrinkage during polymerization so that an initially polymerized portion of the resin is cured into a layer with precise dimensions. For this reason, the polymerization of a dough like resin is preferably initiated from the side of a surface area of plaster cast corresponding to the mucosal surface of a plate denture.
2. Description of the Prior Art
Conventional methods for producing plate dentures include a method in which a dough-like resin is packed into the mold space of a flask after embedding a wax denture (flasking) and wax elimination, followed by immersion of the flask in hot water (heat-curing technique by water bath) and a method in which a flask with the dough packed therein is heated as disposed in between two heated plates (dry heating-curing technique).
According to these conventional methods, a dough-like resin is heated after supply into the mold space of the flask and therefore the polymerization is initiated in the resin locally at different times. When a dough-like resin placed in the mold space is heated, the temperature within the flask is elevated by heat transfer. A denture has a complicated shape which varies from person to person so that after supply, the dough reaches a polymerization-initiating temperature locally at different times. The initially polymerized portion of the dough is given a dimensionally precise configuration, while the other local portions are afforded a dimensionally less precise configuration. Consequently, these conventional methods produce plate dentures in which the configuration of a mucosal surface is not invariably dimensionally precise.
Conventionally it has been also practiced to place a dough-like resin into the mold space after flasking and wax elimination and to heat the flask from the side of a half shell of the flask having a surface area of plaster cast corresponding to the mucosal surface of a denture (hereinafter referred to as "corresponding mucosal surface of plaster cast") so that the polymerization is initiated from this side. However, this method allows the resin to initiate the polymerization locally at different times and to reach the polymerization-initiating temperature locally at different times and fails to invariably produce plate dentures having a mucosal surface of dimensionally precise configuration, by the same reasons as stated above concerning the above-mentioned conventional methods.